This application claims the priority benefit of Taiwan application serial no. 90129243, filed Nov. 27, 2001.
1. Field of the Invention
The invention relates in general to a chemical mechanical polishing (CMP) machine. More particularly, the invention relates to an in-line oscillating device mounted on a slurry pipe in a CMP machine.
2. Description of the Related Art
As far as semiconductor processing technology is concerned, surface planarization is an important technology for processing high-density photolithography. A precise pattern transfer is achieved from a plane surface with no drop or no protrusion for avoiding exposure scattering. The planarization technology roughly comprises a spin-on glass (SOG) process and a CMP process. However, after the semiconductor processing technology enters the sub-micron stage, the SOG process does not satisfy the planarization for the sub-micron stage. As a result, the CMP process becomes rarely a global planarization technology for very-large scale integration (VLSI) or ultra-large scale integration (ULSI). In the CMP process, a reagent of slurry is sprayed on a polishing pad and for reacting to an active surface of a wafer, causing the active surface to form an easy-polishing layer. Thereafter, the protrusion area of the easy-polishing layer of the wafer positioned on the polishing pad is polished. Repeating the above chemical reaction and mechanical polishing can form a planar surface. Basically, the CMP process is a planarization technology in which a mechanical polishing principle is applied with an adaptable reagent and abrasive particles.
Referring to FIG. 1, it is a schematic view illustrating how slurry is transmitted to a CMP machine using a slurry pipe according to prior art. A CMP machine 110 essentially comprises a polishing platform 114, a polishing pad 112 positioned on the polishing platform 114, a holder for grasping a polished body, and a slurry pipe 101 for supplying slurry. The slurry pipe 101 are composed of a main pipe 100, a transmitting pipe 102, a backflow pipe 104, a filter 106, and a peristalsis pump 108. When the CMP process is performed, the peristalsis pump 108 transmits the slurry from the main pipe 100 to the transmitting pipe 102. Through the filter 106, the particles whose size are unfit are filtered out from the slurry being transmitted to the transmitting pipe 102. Thereafter, the slurry is transmitted to the polishing pad 112. When the CMP process is not performed, the slurry in the transmitting pipe 102 flows back into the main pipe 100 through the backflow pipe 104. However, the slurry particles can deposit or stick at a corner of the pipe or at the connecting area between the, backflow pipe 104 and the transmitting pipe 102.
In the conventional slurry pipe, the slurry particles can deposit or stick at a corner of the pipe or at the connecting area between the pipes. The deposited chunks of slurry particles are so large that a wafer can be scratched thereby during the CMP process.
Accordingly, it is an objective according to the present invention to provide an in-line oscillating device. The in-line oscillating device can oscillate the slurry particles in the slurry pipe so that it is difficult for the slurry particles to deposit and stick on the pipe walls. Therefore, the wafer will not be scratched.
To achieve the foregoing and other objects, the present invention provides an in-line oscillating device essentially composed of an oscillating tank, an oscillating pipe, and an oscillating generator. The oscillating pipe is equipped in the oscillating tank and connects with a slurry pipe. The oscillating pipe is constructed from, for example, a snake-like pipe and two connecting pipes. The both ends of the snake-like pipe connect with the slurry pipe respectively through the connecting pipes. The oscillating generator for generating ultrasonic waves is mounted on the oscillating tank. Moreover, the oscillating tank is filled with a medium, such as deionized water, for transmitting the ultrasonic waves generated by the oscillating generator to the oscillating pipe.
The oscillating tank of the present invention is provided with a medium inlet for injecting the medium into the oscillating tank and a medium outlet for discharging the medium from the oscillating tank.
The design of the connecting pipes of the present invention can be determined by the slurry pipe. For instance, the connecting pipes can be a beeline type, a branch type or other types.
The oscillating generator of the present invention is composed of a controller and at least one oscillator. The controller can control the oscillator to generate ultrasonic waves,
The in-line oscillating device of the present invention can be mounted on any location of the slurry pipe where oscillation is needed. A variety of connecting pipes can connect the in-line oscillating device and the slurry pipe.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.